1. Technical Field
This invention relates to an image forming apparatus, a developing device and an image forming method using a toner carrier roller having a regular convexo-concave pattern on a surface thereof.
2. Related Art
In techniques for developing an electrostatic latent image carried on an image carrier with toner, an apparatus is widely used which includes a toner carrier roller which is shaped approximately like a cylinder, carries toner on a surface thereof, and is arranged opposed facing the image carrier. For the purpose of improving the characteristics of toner carried on the surface of such a toner carrier roller, the applicant of the present application has earlier disclosed a structure of a toner carrier roller having a cylindrical shape that the surface of the roller includes convex sections which are regularly arranged and a concave section which surrounds the convex sections (JP-A-2007-121948). Since the concavo-convex patterns in the surface are regulated and uniform, such a structure is advantageous in that it permits easy control of the thickness of a toner layer which is carried on the surface of the roller, the charge level and the like.
In an image forming apparatus constructed as described above, a seal which comes into contact with a developing roller surface is provided in a clearance between a developing roller as a toner carrier roller and a developer housing to prevent the leakage of toner.